Stenotic Diseases Flashcards
Definition of stenosis
- Narrowing in the outflow tract
What type of hypertrophy occurs secondary to stenosis?
- Pressure overload, so it’s a concentric hypertrophy
What are the two types of pulmonic stenosis?
- Dysplastic
- Hypoplastic
Which is preferred for type of stenosis: dysplastic or hypoplastic?
- Dysplastic
What occurs in dysplastic stenosis?
- Fused valve, so it only opens a very small hole
What occurs in hypoplastic stenosis?
- Too narrow to begin with
Who gets pulmonic stenosis?
- Small breeds
- TERRIERS (pitbulls)
- Brachiocephalic dogs
Where is the PMI for the murmur in PS?
- Left heart base
Timing of the murmur for PS?
- Systolic
Quality of the murmur for PS?
- Ejection type murmur (crescendo-decrescendo
Additional murmur that can happen with PS if progresses?
- Tricuspid regurgitation
What is the PMI, timing, and quality of a tricuspid regurgitation murmur that occurs secondary to pulmonic stenosis?
- PMI (right apex) = tricuspid
- Timing is systolic
- Quality is regurgitant/plateau/band
Pulmonic stenosis femoral pulse quality
- Normal
- May have pulse deficits
Can you have jugular pulses with PS?
- Yes, you can
- Possible to have jugular distention and pulses
- Will not always be present
Arrhythmias with pulmonic stenosis - are they possible?
- Yes
- Can cause pulse deficits
Other physical exam findings with PS?
- May have ascites secondary to right heart failure
Appearance of radiograph for a dog with pulmonic stenosis?
- Main pulmonary artery will be enlarged due to post-stenotic dilatation
- Right atrial enlargement
- Right ventricular enlargement
Appearance of pulmonic stenosis on echocardiogram
- Concentric hypertrophy of the right ventricle
- Right ventricular free will can be much larger than the left ventricular lumen
- Pulmonic valve will be small
- Can see a post-stenotic dilatation
What determines severity of pulmonic stenosis?
- How wide does it open?
- If it opens just a tiny bit, that’s very severe
- Creates more extra pressure
How do you determine how much pressure is on the right heart secondary to pulmonic stenosis?
- Pressure ~= velocity
- Can use the modified Bernoulli equation
- ∆P = 4v^2
Make sure you can go through the calculations for the right ventricle based on the velocity of flow through the stenotic valve
just make sure you can do it
Normal pulmonary artery pressure
- 20
Normal right ventricular pressure
- 20 during systole
- 5 during diastole
What is considered mild pulmonic stenosis PA velocity and RV-PA gradient?
PA velocity: 2.5-3.5 m/s
Gradient: 30-50 mmHg
What is considered moderate pulmonic stenosis PA velocity and RV-PA gradient?
PA velocity: 3.5-4.5 m/s
Gradient: 50-80 mmHg
What is considered severe pulmonic stenosis PA velocity and RV-PA gradient?
PA velocity: >4.5 m/s
Gradient: >80 mm Hg
What is the treatment of choice for most cases of pulmonic stenosis?
- Balloon valvuloplasty
Balloon valvuloplasty procedure details
- Catheter in the jugular vein
- Insert it into the heart at the level of the pulmonic valve
- Trying to measure the annulus size
- Can see a little filling defect
What size balloon do you pick?
- should be 1.5x the size of the annulus
What will cardiac output be as the balloon is inflated?
- Crappy
What can happen to the rhythm of the heart as you inflate the balloon?
- Often can go into V-tach
Success rate of balloon valvuloplasty?
- 70% success rate
What is considered a “procedural success” for balloon valvuloplasty?
- 50-60% reduction in gradient
- NOT CURATIVE
- Palliative, and depends on the degree of severity that the dog comes in with
Re-stenosis rate after balloon valvuloplasty?
- About 15-20% of dogs will re-stenose, which can occur at any time
What can make a candidate less ideal for balloon valvuloplasty?
- Sub- or supra-valvular stenosis
- Pulmonary annular hypoplasia (if the artery is tiny to begin with :()
Medical management of pulmonic stenosis
- Treatment of diastolic dysfunction with Beta blockers
- Treatment of arrhythmia if present
- Treatment of CHF if present
What is the purpose of beta blockers with diastolic dysfunction?
- Slow heart rate
- Promotes right ventricular filling and perfusion
- Decreased contraction against obstruction
What can occur secondary to concentric hypertrophy if severe?
- Myocardial ischemia
- Can result in some arrhythmias or death
How to treat CHF for PS?
- Furosemide and an ACE inhibitor
- +/- abdominocentesis (remember that it is right sided heart failure)
Anomalous left coronary artery
- Can occur with pulmonic stenosis
- Basically, some animals never have a left coronary artery and get abnormal growth of it
- Unpredictable location, so these are at greater risk
Who is at risk for an anomalous left coronary artery?
- English bulldogs, French bulldogs, boxers
What is a risk that can occur with an anomalous left coronary artery?
- Balloon valvuloplasty may rupture coronary artery
-
Prognosis for PS
- Depends on severity of disease
Prognosis for mild to moderate PS
- May live normal lives
Prognosis for severe PS without treatment
- 3 years
Prognosis for severe PS with treatment
- Depends on post-balloon gradient
What can worsen the prognosis for severe PS?
- Congestive heart failure
- Arrhythmias (sudden death!)
- Concurrent congenital heart diseases
What happens in subaortic stenosis?
- The valve is normal, but there is a narrowing below it
Who gets subaortic stenosis?
- Golden retrievers, large breeds, Newfoundlands, Rottweilers, Boxers, German Shepherd dogs
Point of maximal intensity, timing, and quality of SAS murmur?
- Left heart base
- Systolic
- Ejection quality murmur
Radiation murmur with subaortic stenosis
- Can occur due to radiation to the carotid arteries
- Listen to the thoracic inlet
What are your top two differentials for a left heart base murmur?
- Sounds similar to pulmonic stenosis
- Differentiate by looking at the breed and exam findings
What additional murmur can occur with SAS?
- Aortic regurgitation
Aortic regurgitation murmur PM, quality, and timing?
- Left heart base
- Diastolic
- Decrescendo murmur
Femoral pulse quality with SAS
- Normal to weak and late
Jugular distensions or pulses with SAS
- SHould be none
Arrythmias with SAS
- Pulse deficits
- Definitely possible
Radiographic findings with SAS
- Left auricular bulge
- Thoracic aorta has a bulge
- Bulge in the left atrium
- Backpack in left atrium on the lateral view
What type of hypertrophy occurs with SAS?
- Concentric hypertrophy
Echocardiogram findings with SAS
- Mushroom
- Interventricular septum will be thickened
- Left atrium narrower
- Dilation in the region below the aortic valve
- Blood flow will be really fast below the valve
How to determine severity of the subaortic stenosis?
- Again, has to do with the modified Bernoulli equation
- ∆P = 4v^2
- Aortic flow = 5 m/s
Normal aortic pressures
- Systole: 120
Diastole: 80
Normal left ventricular pressures
Systole: 120
Diastole: 6
Ao velocity and LV-Ao gradient for mild disease
Ao velocity: 2.5-3.5 m/s
LV-Ao gradient: 30-50 mmHg
Ao velocity and LV-Ao gradient for moderate disease
Ao velocity: 3.5-4.5 m/s
LV-Ao gradient: 50-80 mmHg
Ao velocity and LV-Ao gradient for severe disease
Ao velocity: >4.5 m/s
LV-Ao gradient: >80 mmHg
Treatment for SAS: Surgical
- Not effective
- Fibromuscular ridge below the valve rather than a problem with the valve itself
Medical management of SAS
- Treat diastolic dysfunction
- Treat arrhythmias if present**
- Treat left-sided CHF if present
How to treat diastolic dysfunction?
- Beta-blockers
What function do beta-blockers have for SAS treatment?
- Slows HR
- Promotes LV filling and perfusion
- Decrease contraction against an obstruction
How to treat left sided heart failure if present in SAS?
- Furosemide
- ACE inhibitors
What are animals with SAS at increased risk for?
- Endocarditis
What should you do for patients with SAS considering the disease they are at increased risk for?
- Aggressive treatment of infections
- Perioperative antibiotics for procedures that cause bacteremia
Prognosis for mild SAS
- Probably live a normal life
Prognosis for moderate to severe SAS
- ~2-4 years
What will worsen prognosis of moderate to severe SAS?
- CHF
- Concurrent congenital heart diseases
- Endocarditis
- Arrhythmias - SUDDEN DEATH!
What can occur because of the concentric hypertrophy with SAS?
- Ischemic injury
- Oxygen starved heart
- Can get VPCs, Ventricular tachycardia, and SYNCOPE or sudden death
